cmd/link: building plugin will fail with -gcflags="-N"

[st0012]

What version of Go are you using (go version)?

go version go1.8.3 linux/amd64

What operating system and processor architecture are you using (go env)?

Go env:

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/go"
GORACE=""
GOROOT="/usr/local/go"
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build529090230=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="1"
PKG_CONFIG="pkg-config"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"

What did you do?

I build a plugin with -gcflags="-N":

go build -buildmode=plugin -gcflags="-N" -o ./main.so ./main.go

I have a repo that can reproduce the issue.
Just run docker build . and it should work.

Note

If I build it without setting gcflags and specifying build mode at the same time, it works. It fails only when both of them are set.

What did you expect to see?

It builds the plugin successfully.

What did you see instead?

Error messages, here's some of them:

runtime.rt_sigaction: nosplit stack overflow
        744     assumed on entry to runtime.sigfwdgo (nosplit)
        624     after runtime.sigfwdgo (nosplit) uses 120
        616     on entry to runtime.dieFromSignal (nosplit)
        592     after runtime.dieFromSignal (nosplit) uses 24
        584     on entry to runtime.setsig (nosplit)
        104     after runtime.setsig (nosplit) uses 480
        96      on entry to runtime.rt_sigaction (nosplit)
        -24     after runtime.rt_sigaction (nosplit) uses 120
runtime.bulkBarrierPreWrite: nosplit stack overflow
        744     assumed on entry to callRet (nosplit)
        704     after callRet (nosplit) uses 40
        696     on entry to runtime.reflectcallmove (nosplit)
        664     after runtime.reflectcallmove (nosplit) uses 32
        656     on entry to runtime.bulkBarrierPreWrite (nosplit)
        -48     after runtime.bulkBarrierPreWrite (nosplit) uses 704
runtime.systemstack: nosplit stack overflow
/usr/local/go/pkg/tool/linux_amd64/link: too many errors

[mvdan]

@st0012 did you try on 1.9rc1?

CC @mdempsky @ianlancetaylor

[st0012]

@mvdan It works on 1.9rc1, thanks!
BTW will you support compiling non-main package to plugin?
I'm trying to use non-main packages as plugin (let's why I wrap them into a main package and compile it), do you have any suggestion on this?

[mvdan]

I have no idea - I'm not involved in the plugin work. Perhaps @crawshaw can answer.

In any case, use https://github.com/golang/go/wiki/Questions for questions.

Thanks!

[st0012]

@mvdan Got it, thanks